The field emission flat light source can be widely used in various illumination fields, owing to the advantages of the former, such as energy-saving, environmental protection, and being able to work in harsh environments (such as high and low temperature environment), the thin, etc. Comparing with the conventional back light module, the field emission flat light source has not only a simple structure, but also a power saving feature, a small size, easy to be large-area flatted, high brightness, thus satisfying the requirements for the future development needs of the flat light source. While the field emission flat light source has irreplaceable advantages in the future of competition in the market, however, there are still some problems to be solved in the practical application.
When the conventional field emission flat light source is applied to the back light module for a liquid crystal display, the anode emitting layer of the field emission light source is close to the liquid crystal panel and is sandwiched between the cathode and the liquid crystal panel. After a long term of bombardment of the anode from the electron emitted from the cathode, the temperature will raise. If the heat is difficult to be dissipated by radiation, the serving life of the liquid crystal panel will be affected, and it may also cause the thermal deformation, even rupture of the anode. In addition, the heat dissipation problem still needs to be solved even not applied to the back light module, because the glass substrate, which is often used as anode, has a relatively poor heat dissipation characteristic. Furthermore, since the anode serves as the light incidence surface, it is difficult to assemble metal heat sink device on the surface of the anode.